Transpiration & Translocation - Organisation P2

Question 1

What is transpiration?

Answer 1

Plants lose water to the air

Question 2

What factors affect transpiration?

Answer 2

• Light intensity
• Temperature
• Air flow
• Humidity

Question 3

How does high light intensity affect transpiration?

Answer 3

High light intensity -> more photosynthesis -> more gas exchange-> stomata opens -> more water loss

Question 4

Why is transpiration less at night?

Answer 4

No photosynthesis means stomata is closed

Question 5

What is used to measure the rate of transpiration?

Answer 5

Potometer

Question 6

How do you find the rate of transpiration?

Answer 6

Distance moved by bubble ÷ time taken to move distance (s)

Question 7

What is the transpiration stream?

Answer 7

Movement of water from the xylem to the leaves from the stomata

Question 8

Explain the process of transpiration

Answer 8

1. Root hair cells absorb water from soil
2. Xylem transports water and mineral ions to other parts of the plant
3. Water is lost by the stomata

Question 9

How does humidity affect the rate of transpiration?

Answer 9

If the air is damp or humid, transpiration is limited.
More humid air - Slower transpiration

Question 10

How does humidity affect the rate of transpiration?

Answer 10

If the air is damp or humid, transpiration is limited.
More humid air - Slower transpiration

Question 11

What direction does the phloem transport substances?

Answer 11

Upwards and Downwards

Question 12

What substances does the phloem transport?

Answer 12

Transports sucrose and amino acids

Question 13

What substances does the xylem transport?

Answer 13

Transports water and minerals to parts

Question 14

What is the vascular bundle?

Answer 14

Phloem and xylem tissue

Question 15

What are sieve tubes in the phloem?

Answer 15

Specialised for transport and have no nucleas only cytoplasm

Question 16

What are companian cells?

Answer 16

Transports substances in the phloem which requires energy - cells provide energy for that so it has lots of mitochondria

Question 17

Examples of plant tissues

Answer 17

• Epidermal tissue
• Palisade mesophyll tissue
• Spongy mesophyll tissue
• Xylem and Phloem
• Meristem tissue

Question 18

What does the epidermal tissue do?

Answer 18

Covered in waxy cuticle - prevents water loss by evaporation

Question 19

What does the upper epidermis do?

Answer 19

Transparent so light can pass through it to the palisade layer

Question 20

What does the palisade layer do?

Answer 20

Lots of chloroplasts, at the top so they get most light

Question 21

What do the ai spaces in the spongy mesophyll do?

Answer 21

Increase rate of difusion in gases

Question 22

What happens when plant has lots of water?

Answer 22

Gaurd cells go plump and turgid - makes stomata open so gases can be exchanged for photosynthesis

Question 23

What happens when a plant lacks water?

Answer 23

Gaurd cells lose water and become flaccid - makes stomata close - stops water vapour from escaping

Question 24

How are gaurd cells adapted?

Answer 24

• Sensitive to light
• Thin outer walls and thickened inner walls make the opening and closing work
• More stomata on undersides of leaves than on the top - lower surface is cooler and shadier so less water lost